The highest land speed for a rail-guided vehicle was set in 1982 by a rocket sled at Holloman Air Force Base in southern New Mexico. The sled was unmanned, but if it had a payload with a mass of 25 kg, the magnitude of the payload’s momentum would have been 6.8 × 104 kg• m/s. What was the speed, in m/s and km/h, of the payload and sled?

Complete these sentences. if a roller coaster train has a potential energy of 1,500 j and a kinetic energy of 500 j as it starts to travel downhill, its total energy isj. once the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 j, and its potential energy decreases to j. when the train reaches the bottom of the track and is traveling along the ground, its kinetic energy isj.